SUMMARYNanocomposites are potential materials that can be used to improve the flame resistance of polymers without the need for halogen-based flame retardants. However, the nanocomposites cannot be used as the only raw material to produce final products as they are too expensive compared with low-cost commodity plastics. Therefore, some types of polyolefin-based floor sheet laminated with nanocomposites film were prepared for the cone calorimetric study to determine the suitable nanocomposites laminated structure for flame resistance. This study found that the polyolefin-based floor sheet laminated with 200 m Nylon-6/montmorillonite nanocomposites film on the surface can reduce the HRR max and the S max significantly; other types of nanocomposites film-laminated floor sheet were not able to reduce their flame resistance in comparison with the normal Nylon-6 film-laminated floor sheet. Meanwhile, based on the gas barrier performance, the higher aspect ratio of clay is assumed to contribute to the higher flame resistance of nanocomposites. Thus, the polyolefin-based floor sheet laminated with Nylon-6/sericite nanocomposites film on the surface was also prepared and examined in the cone calorimetric study. However, the Nylon-6/sericite nanocomposites film surface-laminated floor sheet did not cause a significant reduction in the HRR max and S max compared with the Nylon-6/montmorillonite nanocomposites film surface-laminated floor sheet. The grade determined according to the standard fire test and the mechanical properties of the Nylon-6/montmorillonite nanocomposites film surface-laminated floor sheet satisfied the requirements for floor sheets for Japanese railway vehicles.

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We investigated the effects of alkali-silica reaction (ASR) on delayed ettringite formation (DEF) using mortar test pieces comprising ASR reactive aggregates with added potassium sulfate under various environmental conditions. As a result, it was observed that ASR not only promotes expansion caused by DEF, it causes the expansion to occur prematurely, even under conditions where the amount of sulfate and water supply are not significantly large. The increased DEF expansion could be attributed to microcracks accompanying the progress of ASR at high temperatures, and the decrease in the cured product's pH owing to the consumption of an alkaline component during ASR. However, the final expansion caused by DEF tended to be less in mortars where ASR had occurred.

with a reverse current passing through the cell. well, showing the reversibility of the cells. copper in cupric chloride solutions, since the electrode is not reversible.] The two values agree very [This is a very surprising resnlt for

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